This module is hosted by CSR BC8645 chip to provide high quality sound quality and compatibility, and overall performance is superior. The Bluetooth module adopts the driver-less mode.Customer only needs to connect the module to the application product, and can quickly realize the wireless transmission of music and enjoy the fun of wireless music. Supports high-quality sound APT-X digital transmission, and can connect two main Bluetooth devices at the same time. After the module is powered on, it automatically connect to the last paired mobile phone. The second-to-last paired mobile phone needs to be manually connected. If the 6 paired devices are turned on at the same time, the last paired phone is automatically connected. First Type: No DC isolated power supply: suitable for lithium battery-powered, making Bluetooth-compatible headset. Parameters: With call function, CSR8645 low power consumption, power on the boot, the default volume of the largest Using TI amp TPA6132, better sound quality GND, BAT: Powered by a 3.7V lithium battery. GND, VCC: DC 12V power supply OUTL, AGND, OUTR: for the balanced output, can be directly connected headphones, amplifiers, audio and other input devices. COM: is the common side of the button, the other end of the key are then VOL +, VOL-, PREV, NEXT, PLY M +, M-: is the positive and negative of the microphone. Amplifier board size: 2.9 x 2.9CM Colour: Green Material: PCB+plastic+metal Package Contents: 1 x CSR8645 Bluetooth Audio Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.